Castellucci Andrea, Pepponi Emanuela, Bertellini Annalisa, Senesi Caterina, Bettini Margherita, Botti Cecilia, Martellucci Salvatore, Malara Pasquale, Delmonte Silvia, Crocetta Francesco Maria, Fornaciari Martina, Lusetti Francesca, Bianchin Giovanni, Ghidini Angelo
ENT Unit, Department of Surgery, Azienda USL - IRCCS di Reggio Emilia, Reggio Emilia, Italy.
Department of Radiology, Azienda USL - IRCCS di Reggio Emilia, Reggio Emilia, Italy.
Front Neurol. 2021 Jan 13;11:608838. doi: 10.3389/fneur.2020.608838. eCollection 2020.
We describe a rare case of posterior semicircular canal (PSC) fibrosis following acute labyrinthine ischemia in the territory supplied by the common cochlear artery (CCA) and review the relevant literature. A 71-year-old man with multiple vascular risk factors presented 12 days after the onset of acute vertigo and profound left-sided hearing loss. Right-beating spontaneous nystagmus with downbeat components elicited by mastoid vibrations and headshaking was detected. The video head impulse test (vHIT) revealed an isolated hypofunction of the left PSC, whereas vestibular evoked myogenic potentials (VEMPs) showed ipsilateral saccular loss. The clinical presentation and instrumental picture were consistent with acute ischemia in the territory supplied by left CCA. Compared to previous imaging, a new MRI of the brain with 3D-FIESTA sequences highlighted a filling defect in the left PSC, consistent with fibrosis. Hearing function exhibited mild improvement after steroid therapy and hyperbaric oxygen sessions, whereas vHIT abnormalities persisted over time. To the best of our knowledge, this is the only case in the literature reporting a filling defect on MRI, consistent with semicircular canal fibrosis following acute labyrinthine ischemia. Moreover, PSC fibrosis was related with poor functional outcome. We therefore suggest using balanced steady-state gradient-echo sequences a few weeks following an acute lesion of inner ear sensors to detect signal loss within membranous labyrinth consistent with post-ischemic fibrosis. Besides addressing the underlying etiology, signal loss might also offer clues on the functional behavior of the involved sensor over time. In cases of acute loss of inner ear function, a careful bedside examination supplemented by instrumental assessments, including vHIT and VEMPs, of vestibular receptors and afferents may be completed by MRI with balanced steady-state gradient-echo sequences at a later time to confirm the diagnosis and address both etiology and functional outcome.
我们描述了一例罕见的在总耳蜗动脉（CCA）供血区域急性迷路缺血后出现后半规管（PSC）纤维化的病例，并回顾相关文献。一名有多种血管危险因素的71岁男性，在急性眩晕发作及左侧严重听力丧失12天后就诊。检测到由乳突振动和摇头诱发的带有下跳成分的向右自发性眼球震颤。视频头脉冲试验（vHIT）显示左侧PSC单独功能减退，而前庭诱发肌源性电位（VEMP）显示同侧球囊功能丧失。临床表现和影像学表现与左侧CCA供血区域的急性缺血一致。与之前的影像学检查相比，采用3D-FIESTA序列的脑部新MRI突出显示左侧PSC有充盈缺损，符合纤维化表现。类固醇治疗和高压氧治疗后听力功能有轻度改善，而vHIT异常随时间持续存在。据我们所知，这是文献中唯一一例报告MRI上有充盈缺损，符合急性迷路缺血后半规管纤维化的病例。此外，PSC纤维化与功能预后不良有关。因此，我们建议在内耳感受器急性损伤几周后使用平衡稳态梯度回波序列，以检测膜迷路内与缺血后纤维化一致的信号丢失。除了找出潜在病因外，信号丢失还可能为受累感受器随时间的功能行为提供线索。在内耳功能急性丧失的病例中，床边仔细检查辅以对前庭感受器和传入神经的仪器评估，包括vHIT和VEMP，之后可通过MRI平衡稳态梯度回波序列来完成，以确诊并明确病因和功能预后。
